diff --git a/Makefile b/Makefile
index dd8543d..62470dc 100644
--- a/Makefile
+++ b/Makefile
@@ -25,5 +25,13 @@
 .c.o:
 	$(CC) -c $(CFLAGS) $(DEFS) $(INCDIR) -o $@ $< $(LDFLAGS)
 
+# プリプロセスのみ実行して .i ファイルを出力
+pre:
+	@for f in $(CSRCS); do \
+		base=$$(basename $$f .c); \
+		$(CC) -E $(CFLAGS) $(DEFS) $(INCDIR) $$f -o $$base.i; \
+		echo "Preprocessed $$f -> $$base.i"; \
+	done
+
 clean:
-	$(RM) $(OBJS) $(TARGET) core *.o *~ 
+	$(RM) $(OBJS) $(TARGET) core *.o *~ *.i